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IOSR Journal of Dental and Medical Sciences (IOSR-JDMS)
e-ISSN: 2279-0853, p-ISSN: 2279-0861. Volume 10, Issue 3 (Sep.- Oct. 2013), PP 36-40
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Antioxidants in Oral Health and Diseases: Future Prospects
Dr. Nimmi Singh, Dr. Rajarshi Guha Niyogi, Dr Deepak Mishra,
Dr. Mamta Sharma, Dr. Devika Singh
Department of Oral Medicine & Radiology B.I.D.S.H, Patna
Department of Oral Medicine & Radiology B.I.D.S.H, Patna
,RIO,IGIMS,Patna,Bihar
Indira Gandhi Government Dental College & Hospital, Jammu
Post graduate. Department of Oral Medicine & Radiology, S.P.P.I.D.M.S, Lucknow
Abstract: Free radicals have been implicated in the etiology of large number of major diseases. They can
adversely alter many crucial biological molecules leading to loss of form and function. Such undesirable
changes in the body can lead to diseased conditions. Antioxidants are compounds which destroy the free
radicals in the body, thereby preventing against harmful oxidation- reduction reactions. The best sources are
fruits and vegetables which provide a variety of antioxidants like Vit. A, C, E & carotenoids. Currently available
data are compatible with the notion that these vitamins act as chemopreventives against some important
cancers, e.g. carotenoids for lung cancer, ascorbic acid for salivary gland cancer, tocopherols for head and
neck cancers etc. Thus, a greater consumption of fruits and vegetables should be encouraged as they are the
natural sources of these chemopreventive antioxidants. This paper will briefly review the basics of antioxidants
and various scientific studies that bear out the promise of antioxidants for oral care & diseases.
Key words: Antioxidants, chemopreventive, free radicals, carotenoids.
I.
Introduction
Oxygen is an element indispensable for life. When cells use oxygen to generate energy, free radicals
are created as a consequence of ATP (adenosine triphosphate) production by the mitochondria. These byproducts are generally reactive oxygen species (ROS) as well as reactive nitrogen species (RNS) At high
concentrations, they generate oxidative stress, a deleterious process that can damage all cell structures 1.
Oxidative stress plays a major part in the development of chronic and degenerative ailments such as cancer,
arthritis, aging, autoimmune disorders, cardiovascular and neurodegenerative disease The human body has
several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally
produced in situ, or externally supplied through foods and/or supplements. Endogenous and exogenous
antioxidants act as “free radical scavengers” by preventing and repairing damages caused by ROS and RNS, and
therefore can enhance the immune defense and lower the risk of cancer and degenerative diseases2.
II.
Mechanism of action of free radicals
Free radicals are chemically active atoms that have a charge due to an excess or deficient
number of electrons. Free radicals containing oxygen, known as reactive oxygen species (ROS), are the most
biologically significant free radicals.3 In the recent years the term “Reactive Oxygen Species” or “Reactive
Oxygen Intermediates” is a collective term which has been adopted to include molecules like Hydroxyl radical
(.OH ),Superoxide anion (O2 ),Hydrogen peroxide (H2 O2 ),Hypochlorous acid (HCIO)4
While most reactive oxygen species have extremely short half life, they can cause substantial tissue damage by
initiating free radical chain reaction. Reactive oxygen species can cause tissue damage by a variety of different
mechanism which include;
• DNA damage
• Lipid peroxidation (through activation of cyclogenase and lipo oxygenase pathway)
• Protein damage including gingival hyaluronic acid and proteoglycans
• Oxidation of important enzymes eg Antiprotease such as ; 1 antitrypsin
• Stimulation of pro inflammatory cytokine release by monocytes and macrophages by depleting
intracellular thiol compounds and activating nuclear factor
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Antioxidants in Oral Health and Diseases:Future Prospects
Diseases caused by free radicals
Classifications
ENDOGENOUS ANTIOXIDANTS
BILIRUBIN
THIOLS eg. Glutathione, lipoic acid , N
acetyl cysteine
NADPH, NADH
UBIQUINONE (COENZYME Q 10)
DIETARY ANTIOXIDATS
Vitamin C
Vitamin E
β-Carotene
Other carotenoids & oxy carotenoids like
lycopene & lutein
URIC ACID
Polyphenols eg. Flavonoids , flavones,
flavonols & proanthocyanidins
ENZYMESTransferrin( iron)
1. Cu/Zn & Mn dependent superoxide dismutase(SOD)
2. iron dependent catalase
3. selenium dependent glutathione peroxidase
METAL BINDING PROTEINS
Albumin (Copper)
Ceruloplasmin (Copper)
Metallothionin (copper )
Ferritin (iron)
Myoglobin (iron)
HORMONES – Melatonin5
Iain L, C . Chapple et al6
Types of antioxidants
Antioxidants from our diet play an important role in helping endogenous antioxidants for the neutralization of
oxidative stress.
Vitamin C
Vitamin C also known as ascorbic acid, is a water-soluble vitamin. It is essential for collagen,
carnitine and neurotransmitters biosynthesis. Health benefits of vitamin C are antioxidant, anti-atherogenic, anticarcinogenic, immunomodulator.7 Vitamin C works synergistically with vitamin E to quench free radicals and
also regenerates the reduced form of vitamin E. Natural sources of vitamin C are acid fruits, green vegetables,
tomatoes3.
Vitamin E -Vitamin E is a fat-soluble vitamin with high antioxidant potency. Because it is fat-soluble, αtocopherol safeguards cell membranes from damage by free radicals. Its antioxidant function mainly resides in
the protection against lipid peroxidation. The dietary sources of vitamin E are vegetable oils, wheat germ oil,
whole grains, nuts, cereals, fruits, eggs, poultry meat 8. Vitamin E has been proposed for the prevention against
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Antioxidants in Oral Health and Diseases:Future Prospects
colon, prostate and breast cancers, some cardiovascular diseases, ischemia, cataract, arthritis and certain
neurological disorders.9
Beta-carotene- Beta-carotene is a fat soluble member of the carotenoids which are considered provitamins
because they can be converted to active vitamin A. Beta-carotene is converted to retinol, which is essential for
vision. It is a strong antioxidant and is the best quencher of singlet oxygen. Beta-carotene is present in many
fruits, grains, oil and vegetables (carrots, green plants, squash, spinach)5
Selenium- Selenium is a trace element. It forms the active site of several antioxidant enzymes including
glutathione peroxidase. Similar to selenium, the minerals manganese and zinc are trace elements that form an
essential part of various antioxidant enzymes.3 Se is a trace mineral found in soil, water,
vegetables (garlic, onion, grains, nuts, soybean), sea food,meat, liver, yeast. 10 At low dose, health benefits of
Se are antioxidant, anti-carcinogenic and immunomodulators.11
Lycopene- Lycopene has been hypothesized to prevent carcinogenesis and atherogenesis by protecting critical
cellular biomolecules, including lipids, lipoproteins, proteins, and DNA. Lycopene, when given in the dosage of
4.8 mg/day orally for 3 months leads to the reversal of dysplastic changes in leukoplakia 12 and when given in
the dosage of 16 mg/day leads to substantials increase in the mouth opening in oral submucous fibrosis. 13 The
major dietary source of lycopene is tomatoes,with the lycopene in cooked tomatoes, tomato juice and tomato
sauce included, being more bioavailable than that in raw tomatoes.
Flavonoids-They are polyphenolic compounds which are present in most plants. The main natural
sources of flavonoids include green tea, grapes (red wine), apple, cocoa (chocolate), ginkgo biloba, soybean,
curcuma, berries, onion, broccoli. They have been reported to prevent or delay a number of chronic and
degenerative ailments such as cancer, cardiovascular diseases, arthritis, aging, cataract, memory loss, stroke,
Alzheimer„s disease, inflammation, infection. Green tea is a rich source of flavonoids, especially flavonols
(catechins) and quercetin. Catechin levels are 4-6 times greater in green tea than in black tea. Many health
benefits of green tea reside in its antioxidant, anticarcinogenic, antihypercholesterolemic, antibacterial (dental
caries), anti-inflammatory activities14
Omega-3 and omega-6 fatty acids- They are essential long-chain polyunsaturated fatty acids. Dietary sources
of omega-6 fatty acids (linoleic acid) include vegetable oils, nuts, cereals, eggs, poultry. It is important to
maintain an appropriate balance of omega-3s and omega- 6s in the diet, as these two substances work together to
promote health1
Recent antioxidant
Decades of research have proven that precise combinations of the antioxidants phloretin, tetracurcuminoid and
ferulic acid, including formulations applied topically, can neutralize cell-damaging free radicals, particularly
those caused by UV rays, nicotine, alcohol, and hydrogen peroxide. 15 Recent research has further confirmed
that certain antioxidants, including phloretin, silymarin, and hesperetin, significantly inhibit the inflammatory
response associated with Actinobacillus actinomycetemcomitans, one of the pathogens that cause periodontal
disease.16 Lutein; dark green vegetables such as kale, broccoli, kiwi, sprout and spinach . Lignan ; oatmeal
,barley ,rye. Herbs; turmeric (curcumin), grape seed or pine bark extracts They can also provide powerful
antioxidant protection for the body17.
Antioxidant-enzymes
Superoxide dismutase, catalase, and glutathione peroxidase serve as primary line of defense in destroying free
radicals
Mechanism of action of antioxidants3
Antioxidants neutralize free radicals by donating one of their electrons, which ends the electron stealing
reaction. The antioxidant nutrient, however, does not become a free radical by donating an electron because they
are stable in either form. Important antioxidants include the following:
1. Chain breaking or scavenging ones, such as Vitamin E(alpha tocopherol), Vitamin C (ascorbic acid), or
Vitamin A (beta carotene)
2. Preventative antioxidants that function largely by sequestering transition metal ions and preventing Fenton
reactions and are therefore largely proteins by nature (e.g., albumin, transferring, or lactoferrin)
Therapeutic use of antioxidants for oral Lesions4
The possible uses of antioxidants for oral mucosal lesions include the following:
1. Prevention of lesions in high-risk individuals with mucosa that clinically appears normal with no
history of either premalignant or malignant lesion
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Antioxidants in Oral Health and Diseases:Future Prospects
2. The treatment of premalignant oral lesions
3. In patients who have had either premalignant or malignant oral lesions that have been successfully
treated, in order to prevent recurrence of the treated initial lesion or to prevent the development of a
second or a separate primary.
Protective Roles of Micronutrients in Carcinogenesis18
Controversial areas in antioxidants therapy
Current literature reports that a half century of data demonstrates the lack of predictability of
antioxidant therapy and it has not been validated by the scientific method. Widespread use of antioxidants has
failed to quell the current pandemic of cancer, diabetes, and cardiovascular disease or to stop or reverse the
aging process. Antioxidant therapy in human reproductive medicine is controversial. High doses of Vitamin A
may have embryo toxic and teratogenic effects. 19Large doses of ascorbic acid may be associated with the
inhibition of ovarian steroidogenesis and increased probability of abortion.20
III.
Conclusion
The antioxidant micronutrients are important not only for limiting oxidative and tissue damage, but
also in preventing increased cytokine production, which is a result of prolonged activation of immune response.
Dietary and other enzymatic antioxidants protect the lipids of lipoprotein and other biomembranes against
oxidative damage by intercepting oxidants before they can attack the tissues. It is important to have an adequate
antioxidant intake from both diet and supplementation if needed, and can be a valuable adjunct in the treatment
of chronic inflammatory dental disorders. Antioxidants are being widely used in routine general clinical
practice. They are also used in the prevention of cellular damage, the most common pathway for cancer, aging
and a variety of disease. Dietary antioxidants like Vitamin C, Vitamin E, Carotenoids may also be of
significance in the prevention of degenerative disease and maintenance of good health. There is now convincing
evidence that foods containing antioxidants may be of major importance in disease prevention. .
Free yourself from free radicals
Eat more fruits and vegetables
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